JPH073390Y2 - Shutter blade mechanism for camera - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a so-called lens shutter blade mechanism that opens and closes a photographing opening symmetrically with respect to an optical axis in a camera shutter.

[Problems of the prior art] Conventionally, as a mechanism for opening and closing the shutter blade of a so-called lens shutter, which is composed of three or more blades, an annular member (sector ring) uniformly arranged close to each blade is provided. In general, the blade and the member are connected by engaging means by a cam and a pin, and the member is rotated by a charged spring to open and close each blade.

However, recently, a mechanism using an electromagnetic actuator or an electrostrictive element has been increasing in place of a conventional spring as a driving force source of a camera that does not require a charging operation.

Since such actuators have a smaller force than conventional springs, when an annular member having a large mass is operated at high speed, it cannot oppose inertia and is unsuitable for use, and as a result, responsiveness is not always satisfactory. I couldn't say that.

Further, since the annular member has a large sliding area with the guide portion, it is easily affected by changes in temperature and humidity, friction and wear, and there is concern about stability as a whole.

Furthermore, when a detector for detecting the position of the blade for detecting the aperture diameter is arranged, the presence of an annular member having a large area makes it extremely difficult for a camera that is required to be downsized.

[Object of the Invention] The object of the present invention is to eliminate the disadvantages of the above-described conventional mechanism, eliminate the need for an annular member, and facilitate the arrangement of a detector for aperture detection. Is provided.

[Constitution of the Invention] The above-mentioned object of the present invention is such that a driving force source, a rotatably supported shaft, and a slit for position detection on a part of the surface are driven by the driving force source. It is achieved by a main driving blade, a driven blade composed of a plurality of blades, the main driving blade, and a link that suspends the main driving blade and connects the both blades.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view showing an embodiment of the present invention, in which the photographing opening is closed.

FIG. 2 is a plan view showing a state in the middle of exposure, which is also an embodiment of the present invention.

FIG. 3 is a plan view showing the maximum opening state in the embodiment of the present invention.

Reference numeral 1 denotes a base plate, which has a photographing opening 1a which becomes an optical path at the time of exposure in a substantially central portion.

Reference numeral 2 denotes a drive source, which is, for example, an actuator including a motor or the like.

Reference numeral 3 is an actuating lever, one end of which is connected to the output shaft 2a of the drive source 2 and can be rotated by the shaft.

Reference numeral 4 denotes an operation pin, which is planted at the other end of the operation lever 3.

An optical detector 5 generates a signal by detecting the intermittent light.

Reference numeral 6 denotes a main blade, which is rotatably supported on the same axis as the output shaft of the drive source 2 and is fitted to the operation pin 4 at one end thereof and driven by the pin. Also,
A plurality of slits 6a are formed on a part of the blade surface,
The light to the detector 5 is turned on and off.

Reference numeral 7 denotes a driven blade, which is rotatable by a shaft 7a and driven by a connecting link 8.

8 is a connecting link, one end of which is a shaft that is planted on the driving blade 6.
It is pivotally supported by 8a, and the other end is fitted to the driven blade 7 by a shaft 8b.

Reference numeral 9 is also a driven blade, which is supported by a shaft 9a and operates together with the driving blade 6 and the driven blade 9 to open and close the photographing opening 1a.

Reference numeral 10 is also a connecting link, one end of which is supported by the actuating pin 4 on the driving blade 6, and the other end of which is disposed on the driven shaft 9.
Mated by a.

The present invention is configured as described above, and this operation will be described below.

FIG. 1 shows a state before the shutter is operated. In this state, a shutter release switch (not shown) is turned on, and the drive source 2 is energized.

Then, the operating lever 3 starts rotating (clockwise) rightward about the shaft 2a.

Since the actuating pin 4 on the actuating lever 3 also rotates in the same manner, the driving blade 6 rotates clockwise about the shaft 2a and starts opening the photographing opening 1a.

At the same time, the connecting link 8 is driven by the shaft 8a to move the driving blade 6
The driving force is transmitted to the driven blade 7 through the shaft 8b, and the driven blade 7 starts right rotation about the shaft 7a.

Similarly, the driven blade 9 receives the clockwise rotation of the operating lever 3 and the operating pin 4 via the connecting link 10 and starts rotating clockwise by the shaft 9a.

At this time, the shaft 2a, the shaft 8a, the connecting link 8, the shaft 8b and the shaft 7a
The association (X-x, Y-y) consisting of and forms a parallel link.

Similarly, the connecting relationship composed of the shaft 2a, the actuating pin 4, the connecting link 10, the shaft 10a and the shaft 9a also forms a parallel link.

Therefore, since the operation of the two driven blades 7 and 9 and the operation of the main driving blade 6 are substantially the same, it is possible to open symmetrically around the optical axis passing through the photographing opening.

The operation amount of each shutter blade that opens and closes the shooting opening 1a is
A plurality of slits 6a formed on a part of the surface of the driving blade 6
And the optical detector 5 located close to it.

With the clockwise rotation of the driving blade 6, the slit 6a is moved to the optical detector 5
When the detector 5 moves upward and the detector 5 generates a pulse signal, counting is performed by the arithmetic circuit. At the time when a predetermined opening amount and / or exposure time is reached, the control circuit sends a reversing / closing operation command Then, the closing of the photographing opening 1a is started.

The arrangement of the slits for detecting the position / angle / actuation amount / actuation time is on the driven blades 7 and 9 because of the mechanism play necessary for transmitting the driving force via the connecting links 8 and 10. It is easier to obtain a good result when it is provided on the driving blade 6 than when it is provided.

[Other Embodiments] The accuracy of the aperture diameter of the photographing opening by the shutter blade mechanism in the above-described embodiments depends on the link formed around the driving blade.

Normally, in a shutter that constitutes such a parallel link, as shown in FIG.
A straight line X connecting a and the axis 8a, and axes 8b and 8a of the connecting link 8
It is set so that the included angle formed by the straight line Y connecting with and is 90 degrees.

However, in the case of such a setting, if an error occurs when the minimum aperture is selected, there is a disadvantage that it is easily affected by the small aperture aperture. This is particularly noticeable in a program shutter that also serves as an aperture. there were. FIG. 5 is an explanatory view showing a shutter blade mechanism for a camera which eliminates such disadvantages.

A straight line X connecting the axes 2a and 8a and a straight line Y connecting the axes 8b and 8a
Means that when the opening diameter is the minimum (pinhole), the included angle is 90 degrees.

[Advantages of the Invention] As described above, by carrying out the present invention, the mass of the moving member is greatly reduced as compared with the conventional driving by the annular member, so that the moment of inertia is reduced and therefore the high speed operation is achieved. It is possible to obtain a shutter blade mechanism for a camera that can sometimes obtain great effects.

Further, by setting the angle of the parallel link formed by the connecting members to 90 degrees at the minimum aperture size, it is possible to obtain the camera shutter blade mechanism with improved accuracy when the aperture is small.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention, FIGS. 2 and 3 are explanatory views showing the same operation process, and FIGS. 4 and 5 are parallel views of an embodiment of the present invention. It is explanatory drawing which showed the structure of the link. 1 ... Base plate, 1a ... Imaging opening 2 ... Driving source 3 ... Actuating lever 4 ... Actuating pin 5 ... Optical detector 6 ... Driving blade 7,9 ... Driving blade 8,10 ...... Linked link

Claims (2)

[Scope of utility model registration request] 1. A driving blade which is rotatably supported by a shaft, has a slit for position detection on a part of its surface, and is driven by a driving force source; A plurality of connecting members that are respectively suspended between the driving blade and the driven blade to form a link, and when the driving blade is driven by the driving force source, the link is used to link the members. A shutter blade mechanism for a camera that operates with driven blades to open and close the shooting aperture symmetrically with respect to the optical axis. 2. A sandwiching angle formed by an axis connecting the supporting shaft of the driving blade and a shaft supporting portion of the connecting member on the driving blade side and an axis connecting both shaft supporting portions of the connecting member has a minimum opening. The shutter blade mechanism for a camera according to claim 1, characterized in that the shutter blade mechanism is set to 90 degrees when the aperture is set.